<script setup>
import { ref,watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
// 图片列表
defineProps({
    imageList:{
        type:Array,
        default:()=>[]
    }
})
//小图切大图显示
const imageIndex = ref(0)
const enterhandler = (i) =>{
    imageIndex.value = i;
}
//放大镜
const target = ref(null);
const {elementX , elementY , isOutside} = useMouseInElement(target);
//控制滑块跟随鼠标移动（监听elementX/Y变化，一旦变化 重新设置left/top）
const layerLeft = ref(0);
const layerTop = ref(0);
const largeLeft = ref(0);
const largeTop = ref(0);
watch([elementX,elementY],()=>{
    if(!isOutside.value){
        if(elementX.value>100 && elementX.value<300){
            layerLeft.value = elementX.value - 100;
        }else if(elementX.value<=100){
            layerLeft.value = 0;
        }else{
            layerLeft.value = 200;
        }
        if(elementY.value>100 && elementY.value<300){
            layerTop.value = elementY.value - 100;
        }else if(elementY.value<=100){
            layerTop.value = 0;
        }else{
            layerTop.value = 200;
        }
        largeLeft.value = layerLeft.value * 2;
        largeTop.value = layerTop.value * 2;
    }
})
</script>


<template>
  <div class="goods-image">
    <!-- 左侧大图-->
    <div class="middle" ref="target">
      <img :src="imageList[imageIndex]" alt="" />
      <!-- 蒙层小滑块 -->
      <div class="layer" :style="{ left: `${layerLeft}px`, top: `${layerTop}px` }" v-show="!isOutside"></div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li v-for="(img, i) in imageList" :key="i" @mouseenter="enterhandler(i)" :class="{active: i==imageIndex}">
        <img :src="img" alt="" />
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div class="large" :style="[
      {
        backgroundImage: `url(${imageList[imageIndex]})`,
        backgroundPositionX: `-${largeLeft}px`,
        backgroundPositionY: `-${largeTop}px`,
      },
    ]" v-show="!isOutside"></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>